Alcohol consumption raises HDL cholesterol levels by increasing the transport rate of apolipoproteins A-I and A-II.

BACKGROUND: Moderate alcohol intake is associated with lower atherosclerosis risk, presumably due to increased HDL cholesterol (HDL-C) concentrations; however, the metabolic mechanisms of this increase are poorly understood. METHODS AND RESULTS: We tested the hypothesis that ethanol increases HDL-C by raising transport rates (TRs) of the major HDL apolipoproteins apoA-I and -II. We measured the turnover of these apolipoproteins in vivo in paired studies with and without alcohol consumption in 14 subjects. The fractional catabolic rate (FCR) and TR of radiolabeled apoA-I and -II were determined in the last 2 weeks of a 4-week Western-type metabolic diet, without (control) or with alcohol in isocaloric exchange for carbohydrates. Alcohol was given as vodka in fixed amounts ranging from 0.20 to 0.81 g. kg(-1). d(-1) (mean+/-SD 0.45+/-0.19) to reflect the usual daily intake of each subject. HDL-C concentrations increased 18% with alcohol compared with the control (Wilcoxon matched-pairs test, P=0.002). The apoA-I concentrations increased by 10% (P=0.048) and apoA-II concentrations increased by 17% (P=0.005) due to higher apoA-I and -II TRs, respectively, whereas the FCR of both apoA-I and -II did not change. The amount of alcohol consumed correlated with the degree of increase in HDL-C (Pearson's r=0.66, P=0.01) and apoA-I TR (r=0.57, P=0.03). The increase in HDL-C also correlated with the increase in apoA-I TR (r=0.61, P=0.02). CONCLUSIONS: Alcohol intake increases HDL-C in a dose-dependent fashion, associated with and possibly caused by an increase in the TR of HDL apolipoproteins apoA-I and -II.

Metabolic and genetic determinants of HDL metabolism and hepatic lipase activity in normolipidemic females.

The metabolic and genetic determinants of HDL cholesterol (HDL-C) levels and HDL turnover were studied in 36 normolipidemic female subjects on a whole-food low-fat metabolic diet. Lipid, lipoprotein, and apolipoprotein levels, lipoprotein size, and apolipoprotein turnover parameters were determined, as were genetic variation at one site in the hepatic lipase promoter and six sites in the apolipoprotein AI/CIII/AIV gene cluster. Menopause had no significant effect on HDL-C or turnover. Stepwise multiple regression analysis revealed that HDL-C was most strongly correlated with HDL size, apolipoprotein A-II (apoA-II), and apolipoprotein A-I (apoA-I) levels, which together could account for 90% of the variation in HDL-C. HDL size was inversely correlated with triglycerides, body mass index, and hepatic lipase activity, which together accounted for 82% of the variation in HDL size. The hepatic lipase promoter genotype had a strong effect on hepatic lipase activity and could account for 38% of the variation in hepatic lipase activity. The apoA-I transport rate (AI-TR) was the major determinant of apoA-I levels, but AI-TR was not associated with six common genetic polymorphism in the apoAI/CIII/AIV gene cluster.A simplified model of HDL metabolism is proposed, in which A-I and apoA-II levels combined with triglycerides, and hepatic lipase activity could account for 80% of the variation in HDL-C.

Applicability of LDLR flanking microsatellite polymorphisms for prenatal diagnosis of homozygous state for familial hypercholesterolemia.

Analysis of newly identified microsatellite polymorphisms flanking the low density lipoprotein receptor (LDLR) gene was undertaken in the kindred of a child with apparent homozygous LDLR deficiency. The applicability of these approaches to prenatal diagnosis is considered and compared with previous approaches applying functional studies of the LDLR in amniotic fibroblasts.

Effects of shrimp consumption on plasma lipoproteins.

Shrimp is very low in total fat, yet it has a high cholesterol content. Although shrimp is a popular food in the American diet, many people avoid it because of its high cholesterol content. The objective of this study was to test the effect of the addition of cholesterol from shrimp to a low-fat baseline diet as well as to compare the effect of an equal amount of dietary cholesterol derived from shrimp or egg on the plasma lipoprotein pattern of normolipidemic subjects. In a randomized crossover trial, a diet containing 300 g shrimp/d, which supplied 590 mg dietary cholesterol/d, significantly increased low-density-lipoprotein (LDL) cholesterol by 7.1% (P = 0.014) and high-density-lipoprotein (HDL) cholesterol by 12.1% (P = 0.0001) when compared with a baseline diet matched for fat content but containing only 107 mg cholesterol/d. However, because the percentage increase in LDL cholesterol was less than for HDL cholesterol, the shrimp diet did not worsen the ratio of total cholesterol to HDL cholesterol or the ratio of LDL to HDL cholesterol. Moreover, shrimp consumption decreased triacylglycerol (triglyceride) concentrations by 13% (P = 0.004). The diet containing two large eggs per day with 581 mg dietary cholesterol/d also raised LDL- and HDL-cholesterol concentrations compared with baseline, but the percentage increase in LDL cholesterol (10.2%, P = 0.0001) was more than for HDL cholesterol (7.6%, P = 0.004) and there was a trend toward worse lipoprotein ratios. In a comparison of the two high-cholesterol diets, the shrimp diet produced significantly lower ratios of total to HDL cholesterol and lower ratios of LDL to HDL cholesterol than the egg diet as well as lower triacylglycerol concentrations. We conclude that moderate shrimp consumption in normolipidemic subjects will not adversely affect the overall lipoprotein profile and can be included in "heart healthy" nutritional guidelines.

Unique variant of Taussig-Bing heart: double-outlet right ventricle with double ventricular septal defects and double overriding of great arteries.

A cyanotic, tachypneic newborn was diagnosed to have double-outlet right ventricle of the Taussig-Bing type. Cardiac failure did not respond to medical treatment or surgical palliation. Postmortem examination revealed two ventricular septal defects (VSDs), one a malalignment VSD in the membranous septum and adjacent tissue and the other in the anterosuperior part of the muscular septum. The D-malposed aortic root emerged mainly from the right ventricle, with aortic-mitral continuity. The larger posterolateral pulmonary root arose almost entirely from the right ventricle, confluent with the muscular VSD, and unrelated to the mitral valve. Its right ventricular aspect was obstructed by hypertrophied infundibulum. This unique malformation of the heart functioned as a double-outlet right ventricle of Taussig-Bing type. In addition, however, the malformation had elements of tetralogy of Fallot because of the malaligned VSD and hypertrophied conal musculature (although pulmonary flow was excessive), and also of complete transposition of the great arteries because of the arrangements of the two VSDs, which favored aortic flow from right ventricle and pulmonary blood flow from the left ventricle. Thus, a single heart presented similarities to three anatomic and functional entities.